Dura mater occuring between skull and brain protects the brain and inhibits leakage of cerebrospinal fluid. A defect or a contracture of dura mater may be filled with lyophilized products of human dura mater.
However, said lyophilized products of human dura mater have drawbacks such as low homogeneity, short supply, viral infection (Noshinkeigeka; 21(2), 167-170, 1993) and poor biocompatibility with tissue surface due to hardness.
Artificial dura mater made of silicone was developed to solve these drawbacks. However, silicone dura mater, which is not biodegradable, remains in vivo permanently and stimulates peripheral tissue leading to enlargement of granulation tissue and increase of meningorrhagia. Because of these drawbacks, silicone dura mater is disfavored.
In contrast, artificial dura mater made of biodegradable materials, such as collagen (Journal of Biomedical Materials Research; Vol. 25, 267-276 (1991)) and gelatin (Brain and Nerve (No to Shinkei), 21, 1089-1098 (1969)) is not in practical use due to a lack of sufficient strength to suture internal dura mater and artificial dura mater integrally. Human dura mater lyophilized products with the stated drawbacks are, therefore, used because of lack of substitutes.
It is an object of the invention to provide an artificial dura mater free of drawbacks, with sufficient strength for suture, softness so as not to damage a brain surface, modulus of elasticity close to the native dura mater, superior biocompatibility, and biodegradability accompanying repair of damaged tissue.